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  • Rapid Communication

Effect of SU(2) symmetry on many-body localization and thermalization

Ivan V. Protopopov, Wen Wei Ho, and Dmitry A. Abanin
Phys. Rev. B 96, 041122(R) – Published 21 July 2017
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Abstract

The many-body localized (MBL) phase is characterized by a complete set of quasilocal integrals of motion and area-law entanglement of excited eigenstates. We study the effect of non-Abelian continuous symmetries on MBL, considering the case of SU(2) symmetric disordered spin chains. The SU(2) symmetry imposes strong constraints on the entanglement structure of the eigenstates, precluding conventional MBL. We construct a fixed-point Hamiltonian, which realizes a nonergodic (but non-MBL) phase characterized by eigenstates having logarithmic scaling of entanglement with the system size, as well as an incomplete set of quasilocal integrals of motion. We study the response of such a phase to local symmetric perturbations, finding that even weak perturbations induce multispin resonances. We conclude that the nonergodic phase is generally unstable and that SU(2) symmetry implies thermalization. The approach introduced in this Rapid Communication can be used to study dynamics in disordered systems with non-Abelian symmetries, and provides a starting point for searching nonergodic phases beyond conventional MBL.

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  • Received 18 January 2017

DOI:https://doi.org/10.1103/PhysRevB.96.041122

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied PhysicsStatistical Physics & Thermodynamics

Authors & Affiliations

Ivan V. Protopopov1,2,3,4, Wen Wei Ho1,3, and Dmitry A. Abanin1,3

  • 1Department of Theoretical Physics, University of Geneva, 24 quai Ernest-Ansermet, 1211 Geneva, Switzerland
  • 2Institut für Nanotechnologie, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
  • 3Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106, USA
  • 4L. D. Landau Institute for Theoretical Physics RAS, 119334 Moscow, Russia

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Issue

Vol. 96, Iss. 4 — 15 July 2017

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